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Post by mingle on Apr 16, 2008 10:38:46 GMT 10
Hi everyone, I first came across this skull years ago, while I was mowing the lawn - it was tucked away at the base of some shrubs. At first I thought it was a rabbit, but a quick look at the teeth put that idea to rest. I actually lost the skull and just came across it again yesterday (while cutting the grass again!). So I thought I'd take a few pictures and see if anyone here can identify it. From what little research I've done, it's obviously not a rodent and I don't think it's any sort of possum. I'm guessing it's something small, furry, nocturnal and native... It was found on Phillip Island, south of Melbourne... I've taken a few pictures. See what you think:     P.S. Thanks to my daughter for the use of her "Tigger" ruler! :-) Cheers, Mike. |
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Post by Deleted on Apr 16, 2008 10:51:17 GMT 10
jeez Mike....all l ever find are broken pegs & old toys the kids leave out....but not you....oh no....you get to find exciting things like skulls!!!  lt makes a girl not want to start up the lawn mower anymore  l thought maybe it could be a ferret but after looking at the teeth l dont think so...but then again l'm not really sure about this kind of thing  l'll be watching this space to see what the outcome is  Kaz xxx  |
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Post by mingle on Apr 16, 2008 11:07:12 GMT 10
Ha Haa...
Could it be a baby ringtailed possum?
Mike.
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Post by youcantry on Apr 16, 2008 12:28:32 GMT 10
I don't think so. I recently found a brushtail possum skeleton (and kept the skull) and on another day, two other possum jawbones (yet to be identified) and I recall finding an excellent website showing a large number of Australian native skulls. I recall that most, if not all, marsupials have two holes in the upper palate of the mouth but I'd need to see a picture again to know for sure how large these appear. I'll try and track down the website for you... well, actually, I found it pretty quickly, here: museumvictoria.com.au/bioinformatics/mammals/images/thumbplac.htmIt's Victorian fauna no less. Now I'll race you to ID it! |
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Post by youcantry on Apr 16, 2008 12:30:15 GMT 10
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Post by youcantry on Apr 16, 2008 12:54:29 GMT 10
I think the greater glider is closest but it doesn't appear to be an identical match. It's definately a marsupial though. I've only given it a few minutes, but let me know what you come up with.
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Post by molloch on Apr 16, 2008 16:40:24 GMT 10
Ringtail possum with 90% certainty. Maybe young, but no uninterrupted teeth so not too young. The one on the museum site is terrible as a reference skull.
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Post by mingle on Apr 16, 2008 16:57:07 GMT 10
Yeah, after looking, I'd say it appears to be a small ring-tailed possum too...
Strange thing about this skull is that there's one more tooth (well, one more tooth hole) on the left side than the right!
Look at the underside shot of the skull - from the first front tooth on each side, to the first pre-molar, there are 7 on the left and only 6 on the right...
Is this a common thing?
Cheers,
Mike.
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Post by molloch on Apr 16, 2008 19:05:54 GMT 10
I think this may be from a juvenile tooth where the socket hasn't fused over yet? I'm not sure about tooth repalcement in psuedocheirus but it may be that adult teeth do not use juvenile sockets. It looks single rooted so would have to be the canine.
This is about the only thing that says juvenile, the size of the skull is not that indicative, adult ringtail skulls are only around 5-6cm long.
I'll try and find out about the extra socket for you.
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Post by Deleted on Apr 16, 2008 22:04:51 GMT 10
Yep I'll go along with juvenile ringtail. It's closely similar to the photo in Barbara Triggs' book.
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Post by youcantry on Apr 17, 2008 1:32:19 GMT 10
Nope. Still not convinced.  I scaled mingle's photo down to match the scale on the greater glider (top left), then I scaled the museum's image of the common ringtail (top right) to match the greater glider also. Firstly - there's a different number of molar teeth (brown arrows). The premolar is marked with a blue arrow. Secondly I traced some key features using the green line, on mingle's skull. I started at the "top left corner" - i.e. the posterior end of the top jaw, follows the straight line down and to the right, then up and right to the edge of that hole (sorry I don't know the technical terms). From there I went to the "knucklebone" shape at the far right (posterior) - just below that next hole. From there straight down to the mirror image and back to the start. I copied the green line and placed it over the greater glider and the common ringtail without any scaling, etc. The match is fairly close on the greater glider but overshoots the ringtail by a long way. The problem is, however, that when you look at the dorsal surface of the skull there are notable differences between mingle's and the greater glider. Looking only at the dorsal surface, mingle's appears a good match for a brushtail possum, but when you look at the ventral surface there are notable differences; however with the brushy these differences could be due to different parts of the skull having deteriorated between specimens. Even so, the pair of anterior holes in the palate are much smaller on the brushtail. So - something between a brushtail and a greater glider. Being totally unfamiliar with the study of skulls I have no idea how much variation is normal between skull specimens within a species. If there's actually a fair bit (for example - the extra tooth on one side) then I'd go with greater glider. Okay, having said all that I look up the distribution of greater glider and wouldn't you know it, it comes just short of the coast near Phillip Island. If it's a greater glider then it's doing the bobuck trick of being out of range. Not so simple, is it? I'm not sure what it is  |
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Post by youcantry on Apr 17, 2008 10:27:02 GMT 10
Okay.. reading Triggs' book - it says the number of cheek molars can be variable !?!?! what the? That's news to me - in which case half the argument falls over - but the green outline is still interesting.
(I didn't realise that within a species the number of teeth could be variable. Stripes on a thylacine, maybe, but teeth? Isn't that the sort of thing that defines subspecies? It says something for my question of how much variation there can be in skulls!)
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Post by molloch on Apr 17, 2008 18:44:32 GMT 10
That museum reference skull is very misleading.
All Pseudocheiridae (family including ringtails, greater gliders and other gliders (but not brushtails) all have the same dental formulae to my knowledge (3,1,3,4 Upper from memory) - so thats not a reliable difference. Molars can vary, but usually don't - it's the museum skull that is abnormal, not Mingles - I think the museum skull is a juvenile.. I assume the Triggs book you have is scats, tracks and other signs, check out the skull in there. I'm out of town at present but can give you some more reference pics when I get home.
The museum pic also has the brain case opening looking like it faces more ventrally, hence the green lines don't match well. The greater glider probably has a very similar skull to ringtail, and it may come down to some crenulations on the molars or something to get a differnetial.
The skull does seem more elongate at the front in the glider? I can't say it's not one without the skull in my hand, but would be unlikely. I'll try and get some pics of some better reference material, I think I only have Brushtail skull at home though, can't remember...
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Post by mingle on Apr 30, 2008 22:30:31 GMT 10
Hi all...
Thanks for all of the effort that people have put in on this...
So, I'll take it that the final verdict is juvenile rig-tail?
That's what I'm also tending towards, after trolling through lots of books!
Cheers,
Mike.
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l'll be watching this space to see what the outcome is 
